It is possible to inject/lookup an EMF that is derived from a RESOURCE_LOCAL pu. For such EMFs, we need to clarify the behavior for following:
1. Should we disallow specifying jta-data-source
2. If the persistence.xml specifies both non-jta-datasource and javax.persistence.jdbc.* properties, which one should take precedence?
3. If the persitence.xml specifies no database connection information, should we default non-jta-datasource?
3. If the persistence.xml just specifies javax.persitsence.jdbc.* properties, what should be the behavior? Should we still default non-jta-datasource